Answer:
The California Gold Rush sparked a movement west, which only further ignited manifest destiny. People saw the opportunity to stake a claim of their own and truly pursue the "American Dream" out west. This new discovery and the abundance of wealth to be had further solidified support of Polk's decision to move westward.
Explanation:
I think it’s the first option.
The Abolition of Slavery
It was the federal companies that built some of the first road of the nation.
Explanation:
Route 40 or the transnational road came into existence in 1811 as Jefferson and Washington had envisioned for modern roads to connect the whole nation.
This project was done over the next two decades.
These roads were not like the roads we have now whoever.
Those roads which are pave roads of concrete came into existence in 1909 and were mostly built by private companies in this century.
Even now only 70 percent of the roads in US are paved because of the rugged terrains in large parts of the country.